I've just purchased some K550's and I'm not sure which headphone amp to buy to use with them. I listen to all types of music, but mainly rock and pop via FLAC files from my PC to my Rega DAC. My music library includes quite a lot of hi-res files at sample rates of 176.4 & 192kHz. My budget for a headphone amp is up to £300, possibly a bit more to bring the Fidelity Audio HPA-100 into play if the difference will be noticeable through the K550's. On the other hand, will something like the Pro-Ject Head Box II, or moving up the price range to the Graham Slee Novo suffice? I've also just noticed the Reag Ear MkII at £198 which would match my DAC well, can't see any reviews yet though.

My Rega DAC produces quite an 'analogue' sound with good bass, so I wouldn't want to partner it with an overly warm in character headphone amp. Thanks for your views and advice.

I read through this headfonia review, then the 227 comments attached. Looks like the amp recommendations run all over the map. But since you're asking about matching up possibly 3 different component makes (headphone, DAC, amp), your results could be unpredictable. My first guess would be get the amp that matches the DAC.